Isolation and preliminary characterization of temperature-sensitive mutants of Sindbis virus strain AR339.

Summary One hundred and four temperature-sensitive mutants of Sindbis virus strain AR339 have been isolated using five different mutagens. Forty-seven mutants showed no detectable RNA synthesis at the restrictive temperature (39 °C), whereas 57 showed levels ranging from 1% to over 100% of the wild-type level. The mutants did not show complementation. The ratio of the 42S:26S RNA species in cells infected with 30 mutants showing > 10% of the wild-type level of RNA synthesis at 39 °C was measured. Of these 30 mutants, none were found which were wholly defective in production of either RNA species, although the ratio was significantly different from the wild-type for some mutants. Two mutants showed production at 39 °C of polydisperse RNA of both double-stranded and single-stranded types.